Ack/nack feedback method in wireless communication system

ABSTRACT

A method of ACK/NACK feedback in a wireless communication system. The method includes determining, by a UE, a number of public sub-frames, all of which are uplink sub-frame in PCC and any SCC sub-frames of any radio frame in frame structure configurations according to the frame structure configurations of the PCC and any SCC, selecting, by the UE, a configuration, uplink sub-frames of which merely include sub-frames corresponding to the determined number of public sub-frames from existing seven kinds of frame structure configurations, and feeding back, by the UE, to an eNB ACK/NACK information corresponding to PDSCH in the SCC on the PCC adopting a timing relationship between the PDSCH and the ACK/NACK corresponding to the selected configuration.

TECHNICAL FIELD

The present invention relates to a field of mobile communicationtechnology, and more particularly, to an Acknowledgement (ACK)/NonAcknowledgement (NACK) feedback method in a wireless communicationsystem.

BACKGROUND ART

In the 3^(rd) Generation Partnership Project (3GPP) Long Term Evolution(LTE) standard, a downlink transmission technology is based onOrthogonal Frequency Division Multiplexing (OFDM) and an uplinktransmission technology is based on Single-Carrier Frequency DivisionMultiple Access (SC-FDMA).

The LTE system uses two types of frame structure, i.e., frame structuretype 1 adopting Frequency-Division Duplex (FDD) and frame structure type2 adopting Time Division Duplex (TDD). Frame structure type 2 includesseven kinds of frame structure configurations. The proportion ofdownlink sub-frames in each kind of frame structure configuration isfixed, ranging from 40% to 90%. As shown in FIG. 1, it can be clearlyperceived from FIG. 1 that each radio frame consists of 10 radiosub-frames, and numbered sequentially from zero. Take configuration 0for example:

Sub-frame 0 and sub-frame 5 are used for sending downlink data, i.e.,the sub-frame 0 and sub-frame 5 are used by the Evolved NodeB (eNB) forsending information to the User Equipment (UE).

Sub-frames 2, 3 and 4 and sub-frames 7, 8 and 9 are used for sendinguplink data, i.e., the sub-frames 2, 3, 4, 7, 8 and 9 are used by the UEfor sending information to the eNB.

Sub-frame 1 and sub-frame 6 are known as special sub-frames, consistingof three special time slots. The three special time slots arerespectively defined as Downlink Pilot Time Slot (DwPTS), Guard Period(GP) and Uplink Pilot Time Slot (UpPTS). The length of time of theDwPTS, GP, and UpPTS is variable. The specific value of the length ofthe time is configured by the system. The special sub-frames are usedfor sending the downlink data, and can be regarded as truncated downlinksub-frames.

The subsequent evolution of the LTE system is known as the“LTE-Advanced,” called LTE-A for short. An objective of the LTE-A ismeeting system requirements of the International MobileTelecommunications (IMT)-Advanced advanced by the ITU. A criticalenhanced objective of the IMT-Advanced includes further enhanced datarate, interoperability/compatibility with other systems and worldwideroaming characteristics, etc. The objective of the data rate fordownlink is 1Gbps and the objective of the data rate for uplink is500Mbps.

Based on the above objectives, a concept of Carrier Aggregation (CA) isintroduced into LTE version 10. The spectral efficiency of wirelessresources is further improved by aggregating multiple continuous ordiscontinuous carriers into system bandwidth up to 100 Mhz and using theMultiple-Input Multiple-Output (MIMO) technology applied in the LTE-Auplink and downlink. The system of LTE version 10 is already able tomeet the system requirements of the IMT-Advanced. However, in the actualnetwork deployment and system operation, in most cases, competition ofthe spectrum and scattered available spectrum makes such a large-scalecontinuous spectrum aggregation unrealistic. In order to obtain thetarget peak rate of the system of LTE version 10, in the future, thesystem has to adopt the discontinuous spectrum allocation and bandwidthaggregation. While the discontinuous spectrum aggregation means thatthere are big differences between interferences of different frequencybands. Especially for the network deployment of the Time Division(TD)-LTE system, the interference between the uplink and downlinkseverely restricts performances of the TD-LTE system.

Based on the above analysis, in the future evolution of the TD-LTEsystem, an important issue to be considered in the evolution of theTD-LTE system is applying different frame structure configurations todifferent Component Carriers (CC)s. In the system of LTE Rel-10, when aUE is configured with multiple CCs, an eNB notifies the UE of the numberof the Primary Component Carrier (PCC) and the number of aggregatedSecondary Component Carriers (SCC)s through high-level signaling. Inaddition, when the multiple CCs configured for the UE are in differentfrequency bands, and the frame structure configuration of at least oneCC is different from the frame structure of other CCs, how to design atiming relationship between a downlink data sub-frame Physical DownlinkShared Channel (PDSCH) and Uplink (UL) control information, and morespecifically how to feed back the ACK/NACK becomes a key issue to besolved when the carrier aggregation between different bands adoptsdifferent frame structure configurations.

DISCLOSURE OF INVENTION Technical Problem

At present, on the basis of rational technical analysis, the followingtwo solutions are mainly adopted.

The first one is on the assumption that all UEs supporting a carrieraggregation technology between different bands and characteristics ofdifferent frame structure configurations includes at least two PowerAmplifiers (PA)s and Radio frequency (RF) circuits. Specifically, referto the feedback method described in FIG. 2, i.e., when all CCs of the UEare in two different bands and the frame structure configurations ineither a different band are the same, while the frame structure indifferent bands is different, the eNB designates a CC for feeding backACK/NACK information for each UE in each band through the high-levelsignaling. Each band continues to use an existing timing relationshipbetween the PDSCH and UL ACK/NACK in its band according to eachdifferent frame structure configuration. Although this method cansuccessfully feed back the ACK/NACK information, requires that all UEssupporting the carrier aggregation technology between different bandsand characteristics of different frame structure configurations includeat least two PAs, which greatly increases the cost of the Rel-11terminal and restricts the realization and market of the Rel-11products. Further, as for cell edge users with limited power, thecharacteristics of Cubic Metric (CM) needs to be considered when sendingthe UL ACK/NACK information on multiple CCs, and the efficiency of theamplifier of the UE needs to be further reduced, which inevitablydeteriorates the performances of the UL ACK/ANCK and even makes the ULACK/ANCK can not be correctly received for the cell edge users withinsufficient power.

Therefore, the problem of the above method leads to a second method,i.e., merely sending the UL ACK/NACK information on a single PCC toensure that even low-end users with only one PA in the Rel-11 systemstill can benefit from the carrier aggregation technology betweendifferent bands with different frame structure configurations, andcontinue to use the existing power control mechanism of the UL ACK/NACKinformation. A typical method includes: designing a new timingrelationship between the PDSCH and UL ACK/NACK for taking Load Balancing(LB) characteristics of the UL ACK/NACK into account. Although thismethod can correctly feed back the ACK/NACK on the basis of overcomingthe problem of the first method, the biggest concern is that the newtiming relationship between the PDSCH and UL ACK/NACK needs a schedulerto use new scheduling policy for allocating and scheduling resources,i.e., the method needs to change the existing scheduler algorithms.

On the basis of the above analysis, the existing ACK/NACK feedbacktechnical solutions have different problems. Therefore, finding afeasible timing relationship between the PDSCH and UL ACK/NACK, i.e. howto feed back ACK/NACK becomes a primary technical problem of the LTEevolution version 11 to be solved.

Solution to Problem

In view of this, embodiments of the present invention provide anACK/NACK feedback method in a wireless communication system, by whichthe UE may adaptively feed back the ACK/NACK according to the configuredframe structure configuration of the CC, the carrier aggregation betweenBands of different frame structure configurations is effectivelysupported and the coexistence and performance optimization of differentcommunication systems is implemented without limiting the number ofamplifiers of the UE.

In order to achieve the above objective, the technical solution of thepresent invention is accomplished in the following way:

An ACK/NACK feedback method in a wireless communication system includes:

determining, by a UE, number of public sub-frames, all of which areuplink subframe in PCC and SCC sub-frames of any radio frame in framestructure configurations according to the frame structure configurationsof the PCC and any SCC;

selecting, by the UE, a configuration, uplink sub-frames of which merelyinclude sub-frames corresponding to the determined number of publicsub-frames from existing seven kinds of frame structure configurations;and

feeding back, by the UE, to a eNB ACK/NACK information corresponding toPDSCH in the SCC on the PCC adopting a timing relationship between thePDSCH and the ACK/NACK corresponding to the selected configuration.

The method further includes: feeding back, by the UE, to the eNB theACK/NACK information corresponding to the PDSCH in the PCC on the PCCadopting the timing relationship between the PDSCH and ACK/NACKcorresponding to the selected configuration.

The method further includes: feeding back, by the UE, to the eNB theACK/NACK information corresponding to the PDSCH in the PCC on the PCCadopting the timing relationship between the PDSCH and the ACK/NACKcorresponding to the frame structure configuration of the PCC.

When a bundled window of downlink data sub-frames determined by the UEincludes uplink data sub-frames, the method further includes:

mapping the ACK/NACK corresponding to the uplink data sub-frames into aDiscontinuous Transmission, DTX, status, or not feeding back anyACK/NACK in- formation.

When the UE is configured with more than two PCCs, before determining,by the UE, the number of public sub-frames, all of which are uplinksub-frame in PCC and any SCC sub-frames of a radio frame in the framestructure configurations, the method further includes: notifying, by theeNB, the UE of number of PCC for feeding back the ACK/NACK through RadioResource Control, RRC, signaling.

The method for selecting, by the UE, a configuration, uplink sub-framesof which merely include sub-frames corresponding to the determinednumber of public sub-frames from existing seven kinds of frame structureconfigurations includes:

supposing that in any radio frame of the frame structure configurations,a configuration including two uplink and downlink sub-frame switchingpoints is the configuration of the first class and the otherconfigurations are the configurations of the second class, the two kindsof configurations of UE are configuration A and configuration B;

selecting, by the UE, configuration B when configuration A andconfiguration B belong to a same class of configuration, and proportionof uplink sub-frames in configuration A is larger than that ofconfiguration B;

selecting, by the UE, a configuration other than configuration 0 inconfiguration A and configuration B when configuration A andconfiguration B do not belong to a same class of configuration, andeither of configuration A and configuration B is configuration 0;

selecting, by the UE, a configuration other than configuration 6 inconfiguration A and configuration B when configuration A andconfiguration B do not belong to a same class of configuration, andneither of configuration A and configuration B is configuration 0 andeither of them is configuration 6;

selecting, by the UE, configuration 5 when configuration A andconfiguration B do not belong to a class kind of configuration andeither of configuration A and configuration B is configuration 5;

selecting, by the UE, configuration 4 when (A, B) is (1, 3) or (1, 4);and

selecting, by the UE, configuration 5 when (A, B) is (2, 3) or (2, 4).

An ACK/NACK feedback method in a wireless communication system includes:

notifying, by a eNB, a UE of configured information of a PCC and allSCCs through high-level signaling; wherein the configured information ofthe PCC and all SCCs of the UE includes: a frame structure configurationof each CC configured for the UE, and further inlcudes: number of thePCC and all SCCs;

determining, by the UE, a frame structure configuration according to theinformation of the frame structure configurations of the PCC and allSCCs sent from the eNB; and

feeding back, by the UE, to the eNB, ACK/NACK information correspondingto PDSCH in the SCCs on the PCC adopting a timing relationship betweenthe PDSCH and the ACK/NACK corresponding to the determined framestructure configuration.

The method for determining, by the UE, a frame structure configurationaccording to the information of the frame structure configurations ofthe PCC and all SCCs sent from the eNB includes:

supposing that in any radio frame of the frame structure configurations,a configuration including two uplink and downlink sub-frame switchingpoints is the configuration of the first class and the otherconfigurations are the configurations of the second class, the two kindsof configurations of UE are configuration A and configuration B;

determining, by the UE, configuration B when configuration A andconfiguration B belong to a same class of configuration, and proportionof uplink sub-frames in configuration A is larger than that ofconfiguration B;

determining, by the UE, a configuration other than configuration 0 inconfiguration A and configuration B when configuration A andconfiguration B do not belong to a same class of configuration, andeither of configuration A and configuration B is configuration 0;

determining, by the UE, a configuration other than configuration 6 inconfiguration A and configuration B when configuration A andconfiguration B do not belong to a same class of configuration, andneither of configuration A and configuration B is configuration 0 andeither of them is configuration 6;

determining, by the UE, configuration 5 when configuration A andconfiguration B do not belong to a same class of configuration andeither of configuration A and configuration B is configuration 5;

determining, by the UE, configuration 4 when (A, B) is (1, 3) or (1, 4);and

determining, by the UE, configuration 5 when (A, B) is (2, 3) or (2, 4).

The method further includes: feeding back, by the UE, to the eNB theACK/NACK information corresponding to the PDSCH in the PCC on the PCCadopting the timing relationship between the PDSCH and ACK/NACKcorresponding to the determined configuration.

The method further includes: feeding back, by the UE, to the eNB theACK/NACK information corresponding to the PDSCH in the PCC on the PCCadopting the timing relationship between the PDSCH and ACK/NACKcorresponding to the frame structure configuration of the PCC.

When a bundled window of downlink data sub-frames determined by the UEincludes uplink data sub-frames, the method further includes:

mapping the ACK/NACK corresponding to the uplink data sub-frames into aDiscontinuous Transmission, DTX, status, or not feeding back anyACK/NACK information.

In view of the above technical solutions, with the ACK/NACK feedbackmethod in the wireless communication system provided by embodiments ofthe present invention, the UE determines the number of publicsub-frames, all of which are uplink sub-frames in the PCC and SCCsub-frames of any radio frame according to the configured framestructure configurations of the PCC and any SCC, selects theconfiguration, the uplink frames of which merely include sub-framescorresponding to the determined number of the public sub-frames from theexisting seven kinds of frame structure configurations, and feeds backto the eNB the ACK/NACK information corresponding to the PDSCH in theSCC on the PCC adopting the timing relationship between the PDSCH andACK/NACK corresponding to the selected configuration. Alternatively, theeNB notifies the UE of the configured information of the PCC and allSCCs through the high-level signaling. The UE determines a framestructure configuration according to the information of the framestructure configurations of the PCC and all SCCs sent from the eNB, andfeeds back to the eNB the ACK/NACK information corresponding to thePDSCH in the SCCs on the PCC using the timing relationship between thePDSCH and ACK/NACK corresponding to the determined frame structureconfiguration. Further, when the UE is configured with multiple CCs, andthe frame structure configuration of at least one CC is different fromthe frame structure configurations of the other CCs, the method of thepresent invention may adaptively select and determine a timingrelationship between the PDSCH and UL ACK/NACK according to theconfigured frame structure configuration of the CC without changing theexisting algorithm of the scheduler, and feed back the ACK/NACKinformation on the PCC. Therefore, the ACK/NACK feedback method of thepresent invention may effectively support the carrier aggregationbetween Bands of different frame structure configurations and implementthe coexistence and performance optimization of different communicationsystems without limiting the number of amplifiers of the UE.

ADVANTAGEOUS EFFECTS OF INVENTION

The ACK/NACK feedback method of the present invention may effectivelysupport the carrier aggregation between Bands of different framestructure configurations and implement the coexistence and performanceoptimization of different communication systems without limiting thenumber of amplifiers of the UE.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram illustrating frame structureconfigurations of an existing TD-LTE system;

FIG. 2 is a scene schematic diagram illustrating an existing ACK/NACKfeedback method;

FIG. 3 is a work flow chart of ACK/NACK feedback method one according toan embodiment of the present invention;

FIG. 4 is a scene schematic diagram illustrating a first embodiment ofthe present invention for determining ACK/NACK sub-frames;

FIG. 5 is a scene schematic diagram illustrating a second embodiment ofthe present invention for determining ACK/NACK sub-frames;

FIG. 6 is a scene schematic diagram illustrating a third embodiment ofthe present invention for determining ACK/NACK sub-frames;

FIG. 7 is a scene schematic diagram illustrating a fourth embodiment ofthe present invention for determining ACK/NACK sub-frames;

FIG. 8 is a scene schematic diagram illustrating a fifth embodiment ofthe present invention for determining ACK/NACK sub-frames; and

FIG. 9 is a work flow chart of ACK/NACK feedback method two according toan embodiment of the present invention.

MODE FOR THE INVENTION

The present invention is further described in detail hereinafter withreference to the accompanying drawings to make the objective, technicalsolution and merits thereof more apparent.

The main idea of the present invention is:

UE determines number of public sub-frames, all of which are uplinksub-frames in the PCC and SCC sub-frames of any radio frame in the framestructure configurations according to the configured frame structureconfigurations of the PCC and any SCC. The UE selects a configuration,the uplink frames of which merely include sub-frames corresponding tothe determined number of the public sub-frames, from the existing sevenkinds of frame structure configurations. The UE feeds back to the eNBthe ACK/NACK information corresponding to the PDSCH in the SCC on thePCC adopting a timing relationship between the PDSCH and ACK/NACKcorresponding to the selected configuration.

Alternatively, the eNB notifies the UE of the configured information ofthe PCC and all SCCs through high-level signaling. The configuredinformation of the PCC and all SCCs of the UE includes the framestructure configuration of each CC configured for the UE, and furtherincludes the number of the PCC and all SCCs. The UE determines a framestructure configuration according to the information of the framestructure configurations of the PCC and all SCCs sent from the eNB. TheUE feeds back to the eNB the ACK/NACK information corresponding to thePDSCH in the SCCs on the PCC adopting the timing relationship betweenthe PDSCH and ACK/NACK corresponding to the determined frame structureconfiguration.

FIG. 3 illustrates a work flow of ACK/NACK feedback method one accordingto an embodiment of the present invention. As shown in FIG. 3, the flowincludes:

Block 301: UE determines number of public sub-frames, all of which areuplink sub-frames in the PCC and SCC sub-frames of any radio frame inthe frame structure configurations according to the configured framestructure configurations of the PCC and any SCC.

It should be noted that when the UE is configured with more than twoPCCs, the CC for feeding back the ACK/NACK is one of the PCCs.Therefore, before executing this block, the eNB notifies the UE of thenumber of the PCC used for feeding back the ACK/NACK through the RadioResource Control (RRC) signaling.

Block 302: The UE selects a configuration, the uplink frames of whichmerely include sub-frames corresponding to the determined number of thepublic sub-frames, from the seven kinds of existing frame structureconfigurations.

The UE selects the configuration, the uplink frames of which merelyinclude sub-frames corresponding to the determined number of the publicsub-frames, i.e., selects the frame structure configuration, in whichthe sub-frames except for the uplink sub-frames, i.e. the sub-framescorresponding to the determined number of the public sub-frames aredownlink sub-frames. In this block, the UE selecting the configuration,the uplink frames of which merely include sub-frames corresponding tothe determined number of the public sub-frames, from the seven kinds ofexisting frame structure configurations specifically includes:

Suppose that in the frame structure configuration and any radio frame,the configuration including two uplink and downlink sub-frame switchingpoints is the configuration of the first class and the otherconfigurations are the configurations of the second class. The two kindsof configurations of UE are configuration A and configuration B.

When configuration A and configuration B belong to a same class ofconfiguration, and the proportion of the uplink sub-frames inconfiguration A is larger than that of configuration B, the UE selectsconfiguration B.

When configuration A and configuration B do not belong to a same classof configuration, and either of configuration A and configuration B isconfiguration 0, the UE selects the configuration other than theconfiguration 0 in configuration A and configuration B.

When configuration A and configuration B do not belong to a same classof configuration, neither of configuration A and configuration B isconfiguration 0 and either of them is configuration 6, the UE selectsthe configuration other than configuration 6 in configuration A andconfiguration B.

When configuration A and configuration B do not belong to a same classof configuration and either of configurations A and B is configuration5, the UE selects the configuration 5.

When (A, B) is (1, 3) or (1, 4), the UE selects the configuration 4.

When (A, B) is (2, 3) or (2, 4), the UE selects the configuration 5.

Table 1 shows the result of frame structure configurations selected fromthe two different kinds of the frame structure configurations. As shownin table 1, one is frame structure configuration A, the other one isframe structure configuration B. The UE finds existing configuration Cwhich is backward compatible frame structure configuration with thevalues of configuration A and configuration B. Configuration C may beone of configuration A and configuration B, or may be a new kind offrame structure configuration.

TABLE 1 Frame structure configuration A 0 1 2 3 4 5 6 Frame 0 1 2 3 4 56 structure 1 1 2 4 4 5 1 configuration B 2 2 2 5 5 5 2 3 3 4 5 4 5 3 44 4 5 4 5 4 5 5 5 5 5 5 5 6 6 1 2 3 4 5

Block 303: The UE feeds back to the eNB the ACK/NACK informationcorresponding to the PDSCH in the SCC on the PCC using the timingrelationship between the PDSCH and ACK/NACK corresponding to theselected configuration.

It should be noted that in this block, for the PDSCH of the PCC, twoACK/NACK feedback manners may be adopted. One is the same as that ofSCC, i.e., feeding back the ACK/NACK information on the PCC according tothe timing relationship between the PDSCH and ACK/NACK corresponding tothe selected configuration, That is, the UE may feed back the ACK/NACKinformation corresponding to all downlink data on a single CC, so thatmake the UL ACK/NACK obtained by mapping the PCC and SCC exactly thesame as the timing relationship between the downlink data sub-frames.The other is feeding back the ACK/NACK information on the PCC accordingto the ACK/NACK timing relationship determined by its own framestructure configuration.

It should be noted that, for any configured CC, when the ACK/NACKinformation is fed back according to the timing relationship between thePDSCH and ACK/NACK corresponding to the selected configuration, and abundled window of the downlink data sub-frames determined by the UEincludes the uplink data sub-frames, the ACK/NACK corresponding to theuplink data sub-frames are definitively mapped into a DiscontinuousTransmission (DTX) status, or not feeding back any ACK/NACK information.

At this point, the whole work flow of ACK/NACK feedback method one ofthe present invention is finished. In order to make the method of thepresent invention more apparent, examples are given hereafter fordescription.

Embodiment One

In this embodiment, suppose that the UE is configured with two CCs, thenumber of which is CC0 and CC1. CC0 is PCC and CC1 is SCC. Based on theconsideration of minimized adjacent channel interference, CC0 adoptsframe structure configuration 1, while CC1 adopts frame structureconfiguration 2. Refer to the scene schematic diagram shown in FIG. 4for the method for determining the ACK/NACK sub-frames. As shown in FIG.4, the method includes:

Step 401: The UE determines the number of uplink public sub-frames, i.e.designates the number of the public uplink sub-frames as sub-frame 2 andsub-frame 7 according to the frame structure configurations of PCC andSCC.

Step 402: The UE selects the configuration, i.e., the frame structureconfiguration 2 in Frame Structure 2 (FS2), the uplink sub-frames ofwhich merely include sub-frame 2 and sub-frame 7 from the existing sevenkinds of frame structure configurations according to the result of step401.

Step 403: The UE feeds back the ACK/NACK information for the PCC and allSCCs adopting the timing relationship between the PDSCH and ACK/NACKcorresponding to the frame structure configuration 2 in the FS2.

It should be noted that in this embodiment, the PCC feeds back theACK/NACK information according to the timing relationship between thePDSCH and ACK/NACK corresponding to the selected configuration. Thus,the UL ACK/NACK obtained by mapping the PCC and SCC is exactly the sameas the timing relationship between the downlink data sub-frames.

Specifically, in this embodiment, both the eNB and UE definitely knowthat when specific sub-frames (the characteristics are that in theconfigured CC, this sub-frame is the downlink sub-frame of at least oneCC, and meanwhile is the uplink sub-frame of at least one CC, such as,sub-frames 3 and 8 in FIG. 4) in the bundled window are uplinksub-frames of some CCs, the corresponding ACK/NACK mapping of thespecific sub-frames in the bundled window is the DTC status.

Embodiment Two

In this embodiment, suppose that the UE is configured with two CCs, thenumber of which is CC0 and CC1. CC0 is PCC and CC1 is SCC. Based on theconsideration of minimized adjacent channel interference, CC0 adoptsframe structure configuration 1, while CC1 adopts frame structureconfiguration 3. Refer to the scene schematic diagram shown in FIG. 5for the method for determining the ACK/NACK sub-frames. As shown in FIG.5, the method includes:

Step 501: The UE determines the number of uplink public sub-frames, i.e.designates the number of the public uplink sub-frames as sub-frame 2 andsub-frame 3 according to the frame structure configurations of PCC andSCC.

Step 502: The UE selects the configuration, i.e., the frame structureconfiguration 4 in Frame Structure 2 (FS2), the uplink sub-frames ofwhich merely include sub-frame 2 and sub-frame 3 from the existing sevenkinds of frame structure configurations according to the result of step501.

Step 503: The UE feeds back the ACK/NACK information for the PCC and allSCCs adopting the timing relationship between the PDSCH and ACK/NACKcorresponding to the frame structure configuration 4 in the FS2.

It should be noted that same as embodiment one, the PCC also feeds backthe ACK/NACK information according to the timing relationship betweenthe PDSCH and ACK/NACK corresponding to the selected configuration.

Specifically, in this embodiment, both the eNB and UE definitely knowthat when specific sub-frames (the characteristics are that in theconfigured CC, this sub-frame is the downlink sub-frame of at least oneCC, and meanwhile is the uplink sub-frame of at least one CC, such as,sub-frames 7 and 8 in FIG. 5) in the bundled window are uplinksub-frames of some CCs, this embodiment does not feed back any ACK/NACKinformation for the specific sub-frames in the bundled window.

Embodiment Three

In this embodiment, suppose that the UE is configured with two CCs, thenumber of which is CC0 and CC1. CC0 is PCC and CC1 is SCC. Based on theconsideration of minimized adjacent channel interference, CC0 adoptsframe structure configuration 2, while CC1 adopts frame structureconfiguration 4. Refer to the scene schematic diagram shown in FIG. 6for the method for determining the ACK/NACK sub-frames. As shown in FIG.6, the method includes:

Step 601: The UE determines the number of uplink public sub-frames, i.e.designates the number of the public uplink sub-frames as sub-frame 2according to the frame structure configurations of PCC and SCC.

Step 602: The UE selects the configuration, i.e., the frame structureconfiguration 5 in Frame Structure 2 (FS2), the uplink sub-frames ofwhich merely include sub-frame 2 from the existing seven kinds of framestructure configurations according to the result of step 601.

Step 603: The UE feeds back the ACK/NACK information for the PCC and allSCCs adopting the timing relationship between the PDSCH and ACK/NACKcorresponding to the frame structure configuration 5 in the FS2.

Similarly, in this embodiment, both the eNB and UE definitely know thatwhen specific sub-frames (the characteristics are that in the configuredCC, this sub-frame is the downlink sub-frame of at least one CC, andmeanwhile is the uplink sub-frame of at least one CC, such as, sub-frame3 in FIG. 6) in the bundled window are uplink sub-frames of some CCs,the corresponding ACK/NACK mapping of the specific sub-frames in thebundled window is the DTC status.

Embodiment Four

In this embodiment, suppose that the UE is configured with two CCs, thenumber of which is CC0 and CC1. CC0 is PCC and CC1 is SCC. Based on theconsideration of minimized adjacent channel interference, CC0 adoptsframe structure configuration 2, while CC1 adopts frame structureconfiguration 4. Refer to the scene schematic diagram shown in FIG. 7for the method for determining the ACK/NACK sub-frames. As shown in FIG.7, the method includes:

Step 701: The UE determines the number of uplink public sub-frames, i.e.the sub-frame 2 in the figure according to the frame structureconfigurations of the PCC and SCC.

Step 702: The UE selects the configuration, i.e., the frame structureconfiguration 5 in Frame Structure 2 (FS2), the uplink sub-frames ofwhich merely include sub-frame 2 from the existing seven kinds of framestructure configurations according to the result of step 701.

Step 703: The UE merely feeds back the ACK/NACK information for the SCCadopting the timing relationship between the PDSCH and ACK/NACKcorresponding to the frame structure configuration 5 in the FS2. Whilethe PCC still determines the timing relationship between the PDSCH andACK/NACK according to the frame structure configuration of a real PCC.

It should be noted that in this embodiment, the PCC feeds back theACK/NACK information adopting its own frame structure configuration.

Further, it should be noted that in this embodiment, both the eNB and UEdefinitely know that when specific sub-frames (the characteristics arethat in the configured CC, this sub-frame is the downlink sub-frame ofat least one CC, and meanwhile is the uplink sub-frame of at least oneCC, such as, sub-frame 7 in FIG. 7) in the bundled window are uplinksub-frames of some CCs, this embodiment does not feed back any ACK/NACKinformation for the specific sub-frames in the bundled window.

Embodiment Five

In this embodiment, suppose that the UE is configured with three CCs,respectively in different bands. Suppose that the number of the threeCCs is CC0 (in Band I), CC1 (in Band II) and CC2 (in Band III). CC0 isPCC, CC1 is SCC0 and CC2 is SCC1. Based on the consideration ofminimized adjacent channel interference, CC0 adopts frame structureconfiguration 1, CC1 adopts frame structure configuration 3 and CC2adopts frame structure configuration 0. Refer to the scene schematicdiagram shown in FIG. 8 for the method for determining the ACK/NACKsub-frames. As shown in FIG. 8, the method includes:

Step 800: The UE respectively determines the timing relationship betweenthe PDSCH and ACK/NACK for each SCC with different frame structureconfiguration according to the frame structure configurations of thePCC, SCC0 and SCC1, which specifically includes:

Step 801: The UE determines the number of uplink public sub-frames assub-frame 2 according to the frame structure configurations of PCC andSCC0.

Step 802: The UE selects the configuration, i.e., the frame structureconfiguration 4 in Frame Structure 2 (FS2), the uplink sub-frames ofwhich merely include sub-frame 2 and sub-frame 3 from the existing sevenkinds of frame structure configurations according to the result of step801.

Step 803: The UE determines the number of the uplink public sub-framesas sub-frame 2, sub-frame 3, sub-frame 7 and sub-frame 8 according tothe frame structure configurations of PCC and SCC1.

Step 804: The UE selects the configuration, i.e., the frame structureconfiguration 1 in Frame Structure 2 (FS2), the uplink sub-frames ofwhich merely include sub-frames 2, 3, 7 and 8 from the existing sevenkinds of frame structure configurations according to the result of step803.

Step 805: The UE merely adopts the timing relationship between the PDSCHand

ACK/NACK corresponding to the frame structure configuration determinedin steps 802 and 804 for the SCCs. That is, the UE feeds back theACK/NACK information for SCC0 adopting the timing relationship betweenthe PDSCH and ACK/NACK corresponding to the frame structureconfiguration 4 determined, and feeds back the ACK/NACK information forSCC1 adopting the timing relationship between the PDSCH and ACK/NACKcorresponding to frame structure configuration 1. But, the PCC silldetermines the timing relationship between the PDSCH and ACK/NACKaccording to its frame structure configuration.

It should be noted that in the above embodiments, when the UE isconfigured with more than two PCCs, the eNB notifies the UE of thenumber of the PCC for feeding back the ACK/NACK through the RRCsignaling.

All the above embodiments are illustrating examples, in actualapplication, the PCC not only can feed back the ACK/NACK informationaccording to the timing relationship between the PDSCH and ACK/NACKcorresponding to the selected configuration, but also can feed back theACK/NACK information according its own frame structure configuration.Further, for the specific sub-frames in the bundled window, the ACK/NACKcorresponding to the uplink data sub-frames can be definitely eithermapped into the DTC status, or not feeding back any ACK/NACKinformation.

Corresponding to the flow of method one shown in FIG. 3, FIG. 9 shows awork flow of ACK/NACK feedback method two of the present invention. Asshown in FIG. 9, the flow includes:

Block 901: The eNB notifies UE of the configured information of the PCCand all SCCs through high-level signaling. The configured information ofthe PCC and all SCCs of the UE includes: the frame structureconfiguration of each CC configured for the UE, and further includes thenumber of the PCC and all SCCs.

Block 902: The UE determines a kind of frame structure configurationaccording to the information of the frame structure configurations ofthe PCC and all SCCs sent from the eNB.

In this block, the UE may uniquely determine a kind of backwardcompatible frame structure configuration according to the configuredinformation of the CCs sent from the eNB. The UE determines a kind offrame structure configurations as shown in table 1 according to theinformation of the frame structure configurations of the PCC and allSCCs sent from the eNB, which specifically includes:

Suppose that in the information of the CC configured for the UE and anyradio frame, the configuration including two uplink and downlinksub-frame switching points is the configuration of the first class andthe other configurations are the configurations of the second class. Thetwo kinds of configurations of UE are configuration A and configurationB.

When configuration A and configuration B belong to a same class ofconfiguration, and the proportion of the uplink sub-frames inconfiguration A is larger than that of configuration B, configuration Bis determined.

When configuration A and configuration B do not belong to a same classof configuration, and either of configuration A and configuration B isconfiguration 0, the configuration other than the configuration 0 inconfiguration A and configuration B is determined.

When configuration A and configuration B do not belong to a same classof configuration, neither of configurations A and B is configuration 0and either of them is configuration 6, the configuration other than theconfiguration 6 in configuration A and configuration B is determined.

When configuration A and configuration B do not belong to a same classof configuration and either of configurations A and B is configuration5, configuration 5 is determined.

When (A, B) is (1, 3) or (1, 4), configuration 4 is determined.

When (A, B) is (2, 3) or (2, 4), configuration 5 is determined.

Block 903: The UE feeds back to the eNB the ACK/NACK informationcorresponding to the PDSCH in the SCCs on the PCC adopting the timingrelationship between the PDCH and ACK/NACK corresponding to thedetermined frame structure configuration.

Further, the UE feeds back to the eNB the ACK/NACK informationcorresponding to the PDSCH in the PCC on the PCC adopting the timingrelationship between the PDCH and ACK/NACK corresponding to thedetermined configuration. Alternatively, the UE feeds back to the eNBthe ACK/NACK information corresponding to the PDSCH in the PCC on thePCC adopting the timing relationship between the PDCH and ACK/NACKcorresponding to its own frame structure configuration.

It should be noted that when the bundled window of the downlink datasub-frames determined by the UE includes the uplink data sub-frames, theACK/NACK corresponding to the uplink data sub-frames are definitivelymapped into a DTX status, or not feeding back any ACK/NACK information.

At this point, the whole work flow of ACK/NACK feedback method of thepresent invention is finished.

In brief, with the ACK/NACK feedback method in the wirelesscommunication system provided by embodiments of the present invention,the UE determines the number of public sub-frames, all of which areuplink sub-frames in the PCC and SCC sub-frames of any radio frameaccording to the configured frame structure configurations of the PCCand any SCC, selects the configuration, the uplink frames of whichmerely include sub-frames corresponding to the determined number of thepublic sub-frames from the existing seven kinds of frame structureconfigurations, and feeds back to the eNB the ACK/NACK informationcorresponding to the PDSCH in the SCC on the PCC adopting the timingrelationship between the PDSCH and ACK/NACK corresponding to theselected configuration. Alternatively, the eNB notifies the UE of theconfigured information of the PCC and all SCCs through the high-levelsignaling. The UE determines a frame structure configuration accordingto the information of the frame structure configurations of the PCC andall SCCs sent from the eNB, and feeds back to the eNB the ACK/NACKinformation corresponding to the PDSCH in the SCCs on the PCC using thetiming relationship between the PDSCH and ACK/NACK corresponding to thedetermined frame structure configuration.

Further, when the UE is configured with multiple CCs, and the framestructure configuration of at least one CC is different from the framestructure configurations of the other CCs, the method of the presentinvention may adaptively select and determine a timing relationshipbetween the PDSCH and UL ACK/NACK according to the configured framestructure configuration of the CC without changing the existingalgorithm of the scheduler, and feed back the ACK/NACK information onthe PCC. Therefore, the ACK/NACK feedback method of the presentinvention may effectively support the carrier aggregation between Bandsof different frame structure configurations and implement thecoexistence and performance optimization of different communicationsystems without limiting the number of amplifiers of the UE.

The foregoing only describes preferred examples of the present inventionand is not used to limit the protection scope of the present invention.Any modification, equivalent substitution and improvement withoutdeparting from the spirit and principle of the present invention arewithin the protection scope of the present invention.

1. An Acknowledgement/Non Acknowledgement (NACK) feedback method in awireless communication system, the method comprising: determining, by aUser Equipment (UE), a number of public sub-frames, all of which areuplink sub-frame in Primary Component Carrier (PCC) and any SecondaryComponent Carrier (SCC) sub-frames of any radio frame in frame structureconfigurations according to the frame structure configurations of thePCC and any SCC; selecting, by the UE, a configuration, uplinksub-frames of which merely comprise sub-frames corresponding to thedetermined number of public sub-frames from existing seven kinds offrame structure configurations; and feeding back, by the UE, to anEvolved NodeB, (eNB) ACK/NACK information corresponding to PhysicalDownlink Shared Channel, (PDSCH) in the SCC on the PCC adopting a timingrelationship between the PDSCH and the ACK/NACK corresponding to theselected configuration.
 2. The method of claim 1, further comprising:feeding back, by the UE, to the eNB the ACK/NACK informationcorresponding to the PDSCH in the PCC on the PCC adopting the timingrelationship between the PDSCH and ACK/NACK corresponding to theselected configuration.
 3. The method of claim 1, further comprising:feeding back, by the UE, to the eNB the ACK/NACK informationcorresponding to the PDSCH in the PCC on the PCC adopting the timingrelationship between the PDSCH and the ACK/NACK corresponding to theframe structure configuration of the PCC.
 4. The method of claim 2,wherein, when a bundled window of downlink data sub-frames determined bythe UE comprises uplink data sub-frames, further comprising: mapping theACK/NACK corresponding to the uplink data sub-frames into aDiscontinuous Transmission (DTX) status, or not feeding back anyACK/NACK information.
 5. The method of claim 1, wherein, when the UE isconfigured with more than two PCCs, before determining, by the UE, thedetermined number of public sub-frames, all of which are uplinksub-frame in PCC and any SCC sub-frames of a radio frame in the framestructure configurations, the method further comprises: notifying, bythe eNB, the UE of a number of PCC for feeding back the ACK/NACK throughRadio Resource Control (RRC), signaling.
 6. The method of claim 1,wherein the selecting of, by the UE, the configuration, uplinksub-frames of which merely comprise sub-frames corresponding to thedetermined number of public sub-frames from existing seven kinds offrame structure configurations comprises: supposing that in any radioframe of the frame structure configurations, a configuration includingtwo uplink and downlink sub-frame switching points is the configurationof the first class and the other configurations are the configurationsof the second class, the two kinds of configurations of UE areconfiguration A and configuration B; selecting, by the UE, configurationB when configuration A and configuration B belong to a same class ofconfiguration, and proportion of uplink sub-frames in configuration A islarger than that of configuration B; selecting, by the UE, aconfiguration other than configuration 0 in configuration A andconfiguration B when configuration A and configuration B do not belongto a same class of configuration, and either of configuration A andconfiguration B is configuration 0; selecting, by the UE, aconfiguration other than configuration 6 in configuration A andconfiguration B when configuration A and configuration B do not belongto a same class of configuration, and neither of configuration A andconfiguration B is configuration 0 and either of them is configuration6; selecting, by the UE, configuration 5 when configuration A andconfiguration B do not belong to a same class of configuration andeither of configuration A and configuration B is configuration 5;selecting, by the UE, configuration 4 when (A, B) is (1, 3) or (1, 4);and selecting, by the UE, configuration 5 when (A, B) is (2, 3) or (2,4).
 7. An Acknowledgement (ACK)/Non Acknowledgement (NACK) feedbackmethod in a wireless communication system, the method comprising:notifying, by an Evolved NodeB (eNB), a User Equipment (UE) ofconfigured information of a Primary Component Carrier (PCC), and allSecondary Component Carriers (SCC) through high-level signaling, whereinthe configured information of the PCC and all SCCs of the UE comprises:a frame structure configuration of each Component Carrier (CC)configured for the UE, and further comprises: a number of the PCC andall SCCs; determining, by the UE, a frame structure configurationaccording to the information of the frame structure configurations ofthe PCC and all SCCs sent from the eNB; and feeding back, by the UE, tothe eNB, ACK/NACK information corresponding to Physical Downlink SharedChannel (PDSCH) in the SCCs on the PCC adopting a timing relationshipbetween the PDSCH and the ACK/NACK corresponding to the determined framestructure configuration.
 8. The method of claim 7, wherein, thedetermining of, by the UE, the frame structure configuration accordingto the information of the frame structure configurations of the PCC andall SCCs sent from the eNB comprises: supposing that in any radio frameof the frame structure configurations, a configuration including twouplink and downlink sub-frame switching points is the configuration ofthe first class and the other configurations are the configurations ofthe second class, the two kinds of configurations of UE areconfiguration A and configuration B; determining, by the UE,configuration B when configuration A and configuration B belong to asame class of configuration, and proportion of uplink sub-frames inconfiguration A is larger than that of configuration B; determining, bythe UE, a configuration other than configuration 0 in configuration Aand configuration B when configuration A and configuration B do notbelong to a same class of configuration, and either of configuration Aand configuration B is configuration 0; determining, by the UE, aconfiguration other than configuration 6 in configuration A andconfiguration B when configuration A and configuration B do not belongto a same class of configuration, and neither of configuration A andconfiguration B is configuration 0 and either of them is configuration6; determining, by the UE, configuration 5 when configuration A andconfiguration B do not belong to a same class of configuration andeither of configuration A and configuration B is configuration 5;determining, by the UE, configuration 4 when (A, B) is (1, 3) or (1, 4);and determining, by the UE, configuration 5 when (A, B) is (2, 3) or (2,4).
 9. The method of claim 7, further comprising: feeding back, by theUE, to the eNB the ACK/NACK information corresponding to the PDSCH inthe PCC on the PCC adopting the timing relationship between the PDSCHand ACK/NACK corresponding to the determined configuration.
 10. Themethod of claim 7, further comprising: feeding back, by the UE, to theeNB the ACK/NACK information corresponding to the PDSCH in the PCC onthe PCC adopting the timing relationship between the PDSCH and ACK/NACKcorresponding to the frame structure configuration of the PCC.
 11. Themethod of claim 9, wherein, when a bundled window of downlink datasub-frames determined by the UE comprises uplink data sub-frames,further comprising: mapping the ACK/NACK corresponding to the uplinkdata sub-frames into a Discontinuous Transmission (DTX) status, or notfeeding back any ACK/NACK information.
 12. The method of claim 3,wherein, when a bundled window of downlink data sub-frames determined bythe UE comprises uplink data sub-frames, further comprising: mapping theACK/NACK corresponding to the uplink data sub-frames into aDiscontinuous Transmission (DTX) status, or not feeding back anyACK/NACK information.
 13. The method of claim 10, wherein, when abundled window of downlink data sub-frames determined by the UEcomprises uplink data sub-frames, further comprising: mapping theACK/NACK corresponding to the uplink data sub-frames into aDiscontinuous Transmission (DTX) status, or not feeding back anyACK/NACK information.